How do I rearrange my carrier in my carrier list, example my mark2 carrier is nr 5 in the list but..

You can also select something to attack in world map. In the carrier menu, once you select an individual carrier, there are arrows to the left and right of carrier portrait. Select the desired slot, then scroll through til you get to the desired carrier, then select the assign carrier button

You go to your dock and arrange them by swaping it out with your defense fleet. Example if you want your markll to be #2 on your list when its #5 you set your #2 as your defense fleet and it will become your #1 on the list. Then you set your #5 being your markll as your defense fleet becoming #1 and all that's left to do is place your #2 as your defense fleet becoming #1 as when you started but now your #2 will be your markll.